Sulfurization of lard oil



Patented Dec. 4, 1951 S'ULFURI-ZATION or LARD OIL Elmer H. Sperry,

of, New Jersey ,DrexelHill; Pa., assignor to son Oil Company,Philadelphia,

Pa., a corporation NoDraw-ing. Application May ,.194'9',,

. Claims.

hetsulfurization of lard oil, or blends of lard" oil product'suitablefor use in the compounding of cutting oils, gear lubricants. and othersubstances.

Thezsuliurizatiorr'of. lard-.oil has been known ior-ralong time:Forexample, it has been the,

practicetto. sulfurize lard oil by use of. sulfur or sulfurchlorida.W'hen'usin'g sulfur; say as. flour ofisulfumtheadesiredquantity has beenadmixed with the lard; oil. heated to. a. temperature in therange...of:say 325 4'75?" E, and themixture stirred at such temperatureto cause the desired sulfurization, and to fix thessulfurl Thus,.. ithas been a requisite in the pr1or :-ant*" to employ high temperaturesfor the sulfurization of lard oil. When lard oil is heated to theaforesaid elevated temperatures to cause. dissolution; and fixingjotthe. sulfur therein, the

oil tends to decompose, andproducts having an acridodor are formed. Thisheating of lard oil is accompanied by oxidation of. the oil, resultingin rancidity, color deterioration and large increases in. viscosity.

object ofthis invention is: the. provision of a. process; for the.suliurizationr. of lard oil withoutcausing thexabove-mentioneddecomposition, the formationof productshaving an acrid odor,

or theoxidationand concomitant rancidity and darkening of the oil.

Another object of the invention isgthe provision of-azprocesssfor thesulfurization of lard oil which yields a suliurizedlardoil product whichhas better color and; lower viscosity than is obtained by theconventional high temperature processes.

It has now been discovered that lardoil may be"rapidly-"sulfurized atordinary temperature by contactin hydrogentf sulfide and sulfur dioxideinthepresence oithe lard oil. Thus, the process were present inventioneliminates the disadvantages of" the prior" art high temperatureprocesses, and results in .an improved suliurized product; ashereinafter: fully described.

Irr'carryi'ng out'theprocess of the present inventiom itis preferred tointroduce the hydrogen.

sulfide and sulfur dioxide separately and simultanecusly into the lard011.. If the hydrogen sulfideand sulfur dioxide are premixed beforeintroduction into the lard, oil, elemental sulfur may, be;formed,,f\vhich deposits onv the. walls. of

the' gas conduit and thereby causes. plugging.

so. formed lardpi'l' does'not operate to "sulfurize the lardThisinventionrelatesito a novel; process forand mineral oils, to preparea suliurizedllard' oil for astime: sufficient.

sulfur. which. may pass. into, the.

Serial No. 92,073

is applied. to the reactionmixture Thereaction,

is somewhat exothermi and. hencea slight rise of. temperature may beobserved durin the sulfurization. However, this rise of temperature is.

practically insignificanhandwill seldom, iiever, exceedabout 1-0 F.. Itisbelieved obvious that temperatures somewhat. above. or below that ofthe. environment mayv beremployed, say tempera.- tures-of. from. 50 F.-t T-OOF E, but in no event should a temperature'sufiiciently high tocause the deleterious effects observed in prior art high temperaturesulfurizations above. explained, the present invention provides for therapid.- suliurizationof lard oil at ambient temperature, and: henceelevated temperatures, in general, is unnecessary and. providesnoadvantages over the use of ambient temperature.

The: pressure employed may advantageously be atmospheric. Thus, theprocess may be performed by introducing hydrogen sulfide and sulfurdioxide simultaneouslmbut separately, into lard oil contained in an openvessel. Where the introduction; of: alarge percentage of sulfur into thelard: oil is desired, the processmay advanta'geousl'ybe performed undergreater. than atmospheric pressure, but for most purposes,superatm'ospheric pressures are unnecessary. I I

It is preferred to introduce into the. lard oil aboutZ moles of hydrogensulfide for each mole of suliurdioxide, since, as has been found, thisratio results in the utilization of practically the entire amount of thegases added. The mole ratio of hydrogen sulfide to sulfur dioxide may,however, be varied from about 121 to about 4-:1, and good resultsobtained thereby.

The rate of addition of'the gases to lard oil may be. substantiallyvaried without. deleterious effiects, andthe. rate oisuchladdition isnot con? sidered a critical variable. The 'inost advanbe agitatedduring, the] be. employed. As

the use of even slightly tageous rate of addition will depend largelyupon the design of the apparatus employed; Thus, it is obvious that therate of addition of the gases should not be such that a substantialamount thereof leaves the lard oil without entering into the reaction,and this in turn will depend upon the apparatus design, the agitationsupplied to the reaction mixture, and the like. In general, it ispreferred to add from about 0.1 to 1.0 mole of hydrogen sulfide per hourto 100 grams of lard oil, the rate of addition of sulfur dioxide beingselected to come within the mole ratios above defined. It should benoted that any efliuent gases cannot advantageously be recycled to theprocess because such efiiuent gases, of necessity, consist of a mixtureof hydrogen sulfide, sulfur dioxide, and water vapor, and the use ofsuch mixtures is undesirable, as above explained.

The time required for. sulfurization depends upon the rate of additionof the hydrogen sulfide and sulfur dioxide to a given quantity of lardoil. which in turn depends upon the apparatus design, agitation suppliedto the reaction mixture, and similar variables, and also upon the degreeof sulfurization desired. Accordingly, a determination of theappropriate time for sulfurization in each given application should bemade, and in light of the teachings of the present speci fication, suchdetermination is within the scope of those skilled in the pertinent art.Example 2, set forth hereinafter, is indicative of the time required toobtain a certain degree of sulfurization under the conditions specifiedtherein.

Further preferred embodiments of the present invention employ hydrogensulfide and sulfur dioxide to sulfurize a mixture of mineral oil andlard oil. Thus, where it is desired to prepare, e. g., a cutting oilconsisting of about 90% mineral oil and sulfurized lard oil, a mixtureof the appropriate portions of mineral oil and lard oil may be subjectedto the present process, and the desired composition obtained directlytherefrom. The proportions of mineral and lard oil to employ will, ofcourse, be varied in accordance with the product desired and theapplication contemplated. Thus, mixtures of from 10 to 90 parts ofmineral oil with from 90 to 10 parts of lard oil may be employed in theprocess of the present invention, and the products obtained therefromused directly in applications such as cutting oils, gear lubricants, andthe like, or such mixtures may be further compounded for specialapplications.

The following examples illustrate the process of the present invention,which is not to be con sidered as limited thereby.

EXAMPLE 1 Gaseous hydrogen sulfide was contacted with sulfur dioxide inthe presence of lard oil by simultaneously, but separately, introducingthe gases into about 100 grams of No. 1 lard oil contained in an openvessel. The rates of addition of the gases were about 0.1 mole ofhydrogen sulfide per hour and 0.05 mole of sulfur dioxide per hour, thetotal time of introduction being 6 hours. The process was carried out atambient temperature, and no substantial rise in temperature was observedthroughout the process. After cold stabilization, the product had asulfur content of 5.3%.

EXAMPLE 2 The process of Example 1 was repeated over a period of 12hours, the same conditions of op- 4 eration being employed. Samples werewithdrawn at the end of 3 and 6 hours. The products were stabilized at35 F. for 3 weeks, filtered, and analyzed. The analysis showedsulfurization of the lard oil as follows:

Total sulfur Per cent After 3 hours 3.92 After 6 hours 6.90

After 12 hours 14.05

These data indicated that the efficiency of the process does notdecrease even after relatively large amounts of sulfur had beenintroduced into the lard oil.

EXAMPLE 3 Another room temperature sulfurization according to theinvention was effected upon No. 1 lard oil and also on a 50%-50% blendof N0. 1 lard oil and mineral oil, the process of Example 1 beingsubstantially duplicated. The treatment was continued for twelve hours,and the product stabilized for four months at 35 F. The filteredproducts analyzed:

507 Mineral No. 1 Lard Oil 507 No.1

on iard Oil Gravity. 19. 2. S. U. Viscosity 63/210- 275/ N. P. A. Color8 Di] 4 Di]. TotalS 13.4%--- 4.04%.,

EXAMPLE 5 To compare the product of this invention with that obtained bythe conventional high temperature heating process, lard oil sulfurizedwith sulfur fiour at 350 F. was prepared. Color and viscositymeasurements were made and compared with the comparable product ofExample 4.

Sulfurized Lard Oil Method HzS-I-S 0 Sulfur Flour. S. U. Vis costy63/210 Over 500/210". N. P. A. Color Too dark by Dll.

. It is at once apparent that the color and viscosity improvements aresubstantial.

The sulfurized product of this invention can be compounded to yield agood cutting oil by adding a minor proportion of it to mineral oilsusually employed for the purpose. Also, it can be used to prepare gearlubricants by compounding it with mineral oils of suitable viscosities.

Modification and variation are possible within the scope of the appendedclaims, the foregoing disclosure having for its purpose to set forth theessence of the invention. As illustrative of a modification of thepresent invention is the premixing of hydrogen sulfide and sulfurdioxide immediately prior to their introduction into the lard oil, suchpremixing preferably being performed under substantially anhydrousperature of conditions to minimize the formation of elemental sulfur.However, such a modification is not preferred for the reasonshereinbefore dis cussed.

This application is a continuation-in-part of I my copending applicationSerial No. 775,334, filed September 20, 1947, now abandoned.

I claim:

1. A process of sulfurizing lard oil which comprises contacting hydrogensulfide and sulfur dioxide in the presence of said lard oil at a temfrom50 F. to 100 F.

2. A process of sulfurizing lard oil which comprises simultaneously, butseparately, introducing hydrogen sulfide and sulfur dioxide into lardoil at a temperature of from 50 F. to 100 F.

V and atmospheric pressure.

3. The process according to claim 1 wherein about 2 moles of hydrogensulfide per sulfur dioxide is employed.

4. The process of sulfurizing lard oil which comprises simultaneously,and separately, introducing hydrogen sulfide and sulfur dioxide intolard oil at a temperature of from 50 F., said hydrogen sulfide mole of 1F. to 100 being introduced at a Number Name Date 2,061,019 Carter Nov.17, 1936 2,109,692 Forney Mar. 1, 1939 Borglin Mar. 22, 1938 6 rateofvfrom 0.1 to 1.0 mole per hour per 100 grams of lard oil, and saidsulfur dioxide being introduced at a rate of from 0.025 to 1.0 mole perhour per 100 grams of lard oil.

5. The process of sulfurizing a blend of mineral oil and lard oil whichcomprises contacting hydrogen sulfide and sulfur dioxide in the presenceof a mixture of said mineral oil and lard oil, said contacting beingperformed at a temperature of from 50 F. to 100 F.

ELMER H. SPERRY.

REFERENCES CITED UNITED STATES PATENTS OTHER REFERENCES Mellor,Inorganic Chemistry, vol. 10, 1930, page 92.

1.A PROCESS OF SULFURIZING LARD OIL WHICH COMPRISES CONTACTING HYDROGENSULFIDE AND SULFUR DIOXIDE IN THE PRESENCE OF SAID LIQUID LARD OIL AT ATEMPERATURE OF FROM 50* F. TO 100* F.